Andrew Lloyd Webber will use the Diana memorial concert to showcase his new production of Joseph and the Amazing Technicolor Dreamcoat, he has said.
Andrew Lloyd Webber (bottom left) is a judge on Any Dream Will Do
Lord Lloyd-Webber is seeking a new star for the West End show through BBC One talent contest Any Dream Will Do.
And the winner will make his stage debut in the role at the Concert for Diana at Wembley Stadium on 1 July.
"Everybody who's on it is going to be advertising something on there - it doesn't matter who you are," he said.
"That's what's performers and artists do."
Lord Lloyd-Webber is in charge of a 20-minute slot at the concert and said Any Dream Will Do was one of Princess Diana's favourite songs.
BBC Radio Five Live entertainment reporter Colin Paterson asked Lord Lloyd-Webber about accusations that he would use the occasion for advertising.
"If I'm doing 20 minutes and it was her favourite song, who else would you do it with?" he said. "You might as well do it with your Joseph who's about to open in London."
Previews for the West End show begin five days after the concert, which will be watched by 62,000 people at the stadium and millions more on TV around the world.
The charity concert will mark the Princess of Wales' 46th birthday and the 10th anniversary of her death.
The event has been organised by Princes William and Harry, who said they wanted it to be "the best birthday present" for their mother.
Sir Elton John, Rod Stewart, Take That, Duran Duran and Lily Allen will be among the other performers.
Lord Lloyd-Webber also said the BBC had asked him to extend the run of Any Dream Will Do.
"I said: 'Look, minor problem about extending a programme where you're casting somebody for a West End show - there is a West End show.'
"We go into rehearsal on the Monday after the we do our last programme. I said: 'Very flattering, I don't think we can.'"
A spokesman for the corporation said: "The BBC are delighted with the success of Any Dream Will Do, but presently there are no plans to extend the run."
Lord Lloyd-Webber's fortune was valued at £750m in the recent Sunday Times Rich List - making him richer than Sir Paul McCartney.
But the theatre producer disputed the valuations, saying he had written to the compiler to ask how it was calculated.
"It's all rubbish because what it doesn't say in there is that we've got £120m debt in the theatres," he said.
"I know, I'm jolly lucky. I'm worth about half what it says in there if I sold everything up - it's still a huge amount of money. But it's all fabricated, it seems to me."